a) Field of the Invention
The present invention relates to apparatus and method for controlling a vehicular velocity so as to make the vehicular velocity equal to a target vehicular velocity in order to follow up a preceding vehicle which is traveling ahead of the vehicle at an appropriate inter-vehicle distance.
b) Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 5-104993 published on Apr. 27, 1993 exemplifies a previously proposed preceding vehicle follow-up controlling apparatus for controlling an opening angle of an engine throttle valve for an automotive vehicle and a braking force operatively applied from a vehicular brake system to the vehicle according to a deviation between a safe inter-vehicle distance determined on the basis of a detected value of a vehicular velocity and a relative velocity to a preceding vehicle and a detected value of the inter-vehicle distance.
In such a kind of apparatus described above, a range of a vehicular velocity of the vehicle to be enabled to follow up the preceding vehicle (so-called, a vehicular velocity controllable range, for example, 40 Km/h to 110 Km/h) is prescribed. Then, the preceding vehicle follow-up control to follow up the preceding vehicle at a time point when the vehicular velocity becomes reduced and has exceeded the prescribed lower limit velocity value is released to be ineffective.